1. Field of the Invention
This invention relates to tablet coating compositions, and, more particularly, to such composition having an advantageous combination of physical properties which is a mixture in predetermined proportions of sodium alginate and a polyvinylpyrrolidone-vinyl acetate copolymer.
2. Description of the Prior Art
Hydroxymethyl cellulose is a good film former; however, its films are brittle, opaque and non-slippery. Accordingly, it is desired to provide new and improved tablet coating compositions.
What is described herein is a tablet coating composition which includes a mixture of (a) sodium alginate and (b) a polyvinylpyrrolidone-vinyl acetate copolymer, and, optionally, (c) hydroxypropylmethyl cellulose, and/or hydroxypropyl cellulose.
This composition provides the tablet with a predetermined degree of luster, strength, smoothness, slipperiness, color, modified release and ease of polishing.
In the preferred form of the invention, composition (b) includes by weight, 60-80% vinylpyrrolidone and 20-40% vinyl acetate; preferably the composition has a K-value of about 25 to 34, calculated from its kinematic viscosity on a 1% aqueous solution.
Most preferably, the composition comprises, by weight, (a) 10-98%, (b) 2-20%, and (c) 0-88%.
Application formulations of the composition of the invention include a medicament, and/or a nutritional supplements.
In this invention, tablets are coated with a predetermined mixture of (a) sodium alginate and (b) a polyvinylpyrrolidone-vinyl acetate copolymer, (Plasdone(copyright) S-630, International Specialty Products, Inc.), optionally with hydroxypropylmethyl cellulose, and/or hydroxypropyl cellulose.
Experimental
1. Process/Composition:
Aqueous solutions of sodium alginates (Manucol LD, 5 cps or Keltone LV, 50 cps), and Plasdone(copyright) S-630, and color lakes, were sprayed onto placebo tablets* in a Glatt fluid-bed Wurster coater. The coated tablets were characterized by their weight gain, and, subjectively, for coating uniformity, lustrousness, and slipperiness/tackiness when exposed to aqueous fluids.
* Placebo (lactose) tablets from Korsch Processing laboratory were convex tablets (7.5 mm diameter; average thickness 5.6 mm), and the average tablet weight was 201.3 mg.
2. Fluid Bed Conditions:
Glatt fluid-bed coater with Wurster adapter and plate B.
Batch size 400 g.
Spray rate: 10 g/min
Atomization pressure: 3 bar.
Drying air temperature: 60xc2x0 C.
Flap: 35% open.
3. Coating Procedure and Results: